RE: [Chrysler300] J cylinder head exhaust seats

Hi Jamie, despite the mad rush to put these in, has anyone on server experienced that failure (which is specifically, what? ) on B engine exhaust seat without inserts? Can be an issue , I would expect, on marine or truck engines under high loads, but car engines, I have some trouble buying it. Do not have those in any heads on cars I have built or owned, never had any problems since 62(!) , and inspected engines with 100k + on them at teardown, no evidence of anything. I suspect it is a rumor grown large, from the 283 camp, but emphasize I have an open mind, would like to know of someone who had this happen. What DOES happen??,(! Facts, from examination, not magazine or machine shop opinions)?? If not perfectly done, in terms of fit , they DO fall out, totaling the engine. I do know of that happening to a friend’s engine . Leads to lots of mouth movement at machine shop about why, blame you (somehow) which does not bring back rare heads, even if made whole on $. Further, from engineering view, there is an inefficient seam in heat transfer from inlaid seat to cast iron, solid iron transfers heat better, and heat is the enemy. Plus, amount of iron to water is reduced, I think making it far far easier to crack it. Not “breaking through” but leaving .060 of iron is far worse in fact than breaking through, as you do not know that.. Your machinist is a very smart guy. Antifreeze leak takes out whole engine. (just went through that , cam was round, all rockers totaled inside at shaft) . To answer your specific question, there are ultrasound devices that can measure depth to water jacket, but do you REALLY want to reduce that safety factor over group think?

With respect to burning of exhaust, only engine I know of, personal experience, that that happened on was on propane, and it was valve-- not seat that was badly grooved and burned, that also makes common sense, plain cast iron seat was perfect, not even needing grinding, new valve and Ok since . That seat REALLY surprised me, expected what you talk of, especially with radially grooved valve right against it….but there you have it. Destroyed valve, seat fine. Seat is surrounded by a large mass of iron backed by water. Yet, apparently?? Valve has nothing to worry about,?? yet seat gets hurt, per rumor? Right.

Some quality engines have induction hardened heat treated area around exhaust valve, more for recession or wear than (?” No lead failure—which specifically, is what??”?) , Putting in seats probably nicely removes the elaborate heat treat** . B block might have that , they did something to improve hemi, as early ones had factory stellite hard seats , believe on later ones they deleted it.--- Without problems--- but maybe a really good heat treat. For high performance engines, for sure they would not have forgotten 55-58 hemi racing experience in 59-64. Plus no exhaust seat history on B blocks , (to my knowledge) unlike cheap brand x that does not even have valve guides (except hole drilled in cast iron) , their heads may burn. And they outnumber us.

All of this assumes correct adjustment of solids,--- too tight you burn everything, all bets are off if valve is hung off seat when hot.

My .02, ----do not listen to “everyone knows” BS, think it through…as you are doing. Your thinking is right on. Further if worst prediction happens(it won’t) you do a valve job at 75-100k, still have your J heads, unlike antifreeze and cracking worries.

** had that happen, machine ship proudly turned perfect C or D crank .010 to “clean it up” (read charge you) which removes thin marine/ industrial heat treat the 300 hemi cranks had. Something like nitriding, read that long ago, as a costly feature of 392 letter car cranks . Took me a week to get over that. Not sure I ever did.

John

From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx]
Sent: Thursday, May 22, 2014 9:39 AM
To: 'Chrysler300@xxxxxxxxxxxxxxx'
Subject: [Chrysler300] J cylinder head exhaust seats

Hello group, The machine shop that is working on my J heads asked me if there is enough casting meat to put hardened exhaust inserts in the combustion chambers with the large 300J 1.74 valve diameter? They are reluctant to take a chance on not knowing if anyone has done the inserts on the 557 J head casting and then ruining my rare parts by breaking into the cooling jacket. The senior guy in the machine shop has some experience on a 413 max wedge engine when they went to a 1.81 valve (he does not recall the casting number of those heads) and broke into the jacket when they did the inserts, since the heads were not as valuable to him, He just sourced a set of 915’s that were of a later casting and installed the large 1.81 seats into them without a problem. The factory had apparently changed the mold casting by then to provide more material in that area that allowed them to install the hardened seat. I do not want to run any type of fuel additive as I would like to have the inserts added to my heads but of course will not do the inserts if there is a chance that the 557’s will be damaged during the process. Has anyone on the server installed hardened seats in a J?

Jamie Hyde

585-466-0067 cell